RIGA TECHNICAL UNIVERSITY Faculty of Mechanical Engineering, Transport and Aeronautics Sergejs BRATARČUKS Student of the Doctoral study program “Transport” ASSESSMENT OF TECHNICAL CONDITION OF THE LAND TRANSPORT STRUCTURES AND OBJECTS USING ACOUSTIC EMISSION METHOD Summary of the Doctoral Thesis Scientific Supervisor Professor, Dr. habil. sc. ing. M. BANOVS RTU Press Riga 2017 1 Bratarčuks S. Assessment of Technical Condition of the Land Transport Structures and Objects Using Acoustic Emission Method. Summary of the Doctoral Thesis. – Riga: RTU Press, 2017. – 41 p. Printed according to the decision of the RTU P-22 Board meeting, November 10, 2016, Protocol No. 05/2016 2 DOCTORAL THESIS PROPOSED TO RIGA TECHNICAL UNIVERSITY FOR THE PROMOTION TO THE SCIENTIFFIC DEGREE OF DOCTOR OF ENGINEERING SCIENCES To be granted the scientific degree of Doctor of Engineering Sciences (Transport), the present Doctoral Thesis has been submitted for the defence at the open meeting of RTU Promotion Council “RTU P-22” at RTU Aeronautics institute 1A k-1 Lomonosova Street, Riga, at 14:30 on 2017, September 14th, auditorium 218. OFFICIAL REVIEWERS Professor Dr. habil. sc. ing. Andrey Shaniavski Material Research Division of Aviaregister, Russia Professor Dr. habil. sc. ing. Valdis Priednieks Latvian Maritime Academy Assoc. Professor Dr. sc. ing. Margarita Urbaha Riga Technical University DECLARATION OF ACADEMIC INTEGRITY I hereby declare that the Doctoral Thesis submitted for the review to Riga Technical University for the promotion to the scientific degree of Doctor of Engineering Sciences (Telecommunications) is my own. I confirm that this Doctoral Thesis had not been submitted to any other university for the promotion to a scientific degree. Sergejs Bratarčuks …………………………….(Signature) Date:……………………… The Doctoral Thesis has been written in English language; it consists of an introduction, five sections, conclusions, bibliography, and 10 appendices. It includes 91 figure and 10 tables. The total volume of the Thesis is 200 pages. The bibliography comprises 161 entry. 3 1. TABLE OF CONTENTS GENERAL DESCRIPTION OF THE THESIS....................................................................... 6 CHAPTER 1: THE ANALYSIS OF METHODS FOR ASSESSING THE TECHNICAL CONDITION OF THE LAND TRANSPORT SYSTEMS' STRUCTURES .................................... 10 CHAPTER 2: THE METHODOLOGY OF EXPERIMENTAL AE-EXAMINATION OF DAMAGES OF LAND TRANSPORT CONSTRUCTIONS ..................................................... 11 2.1 The objects of technical condition assessment ........................................................................ 11 2.1.1 Ķegums HPP bridge .......................................................................................................... 11 2.1.2 Locomotive bogie frames and bolsters ............................................................................. 12 2.1.3 Prestressed concrete railway sleepers ............................................................................... 13 2.2 The test objectives .................................................................................................................... 13 2.3 AE registration and measurement equipment .......................................................................... 14 2.4 Ķegums HPP bridge inspection methodology ......................................................................... 15 2.5 The methodology of assessment of 2M62 locomotive bogie frames and bolsters .................. 15 2.6 The methodology of AE testing of prestressed concrete sleepers ........................................... 18 CHAPTER 3: EXPERIMENTAL STUDIES OF THE MECHANISMS OF DAMAGE TO LAND TRANSPORT FACILITIES AND THE EVALUATION OF THE TECHNICAL STATE BY THE METHOD OF ACOUSTIC EMISSION ............................................................... 19 3.1 Application of AE in the assessment of Ķegums HPP bridge ................................................. 20 3.2 Assessment of the 2M62 locomotive bogie frames and bolsters ............................................. 20 3.3 Features of behavior of AE signals at dynamic bench tests of prestressed concrete sleepers . 21 CHAPTER 4: INVESTIGATION OF DAMAGES OF MODERN COMPOSITE MATERIALS AND DEVELOPMENT OF ASSESSMENT CRITERIA USING THE SPECTRAL PROPERTIES OF AE-SIGNALS ........................................................................ 26 4.1 Description of the subject area ................................................................................................. 26 4.2 Material characteristics ............................................................................................................ 27 4.3 Research objectives .................................................................................................................. 27 4.4 Test methods ............................................................................................................................ 27 4.5 Test results ............................................................................................................................... 30 4.6 Chapter summary ..................................................................................................................... 31 CHAPTER 5: MATHEMATICAL ANALYSIS OF SPECTRAL AND DYNAMIC CHARACTERISTICS OF AE-SIGNALS AND DEVELOPMENT OF A MATHEMATICAL METHOD FOR IDENTIFYING THE STAGES OF MATERIAL DESTRUCTION ...................... 31 5.1 Problem description ................................................................................................................. 31 5.2 The problem of compatibility of AE systems .......................................................................... 31 5.3 Data normalization function..................................................................................................... 31 5.4 Determination of dynamic α1 и α2 criteria using the “smoothing” function ............................ 32 5.5 Development of the program AE frequency analysis .............................................................. 33 5.6 Determination of the maximum frequency power spectrum density ....................................... 34 5.7 Determination of α-criterion connection with the spectral characteristics of AE signals during destruction of epoxy composite .......................................................................................... 35 4 5.8 Method verification .................................................................................................................. 38 CONCLUSIONS .................................................................................................................... 39 BIBLIOGRAPHY .................................................................................................................. 40 5 GENERAL DESCRIPTION OF THE THESIS Research topicality Transport is one of the most important sectors of the economy, shaping and defining the opportunities for the development of all other areas of the activity of the modern countries. The constantly increasing demand for more intense, high-speed ground transportation systems results in the use of all elements of the transport infrastructure with increasing loads. The wheels of locomotives, wagons, and axle trucks are subject to the complex effects of fatigue loads, shock loads, and other impacts. In January 2014, a new policy was adopted by the EU on the development of transport infrastructure. This policy is related to the gradual deployment of the transport infrastructure projects of TEN-T (Trans-European Transport Networks), which began in the early 1990s. The planned date of the implementation of the project is year 2030, with 24.05 bn. € of the draft budget to be spent until 2020 [7]. The task of the group of projects TEN-T is to improve the opportunities for economic growth and bring together the individual European national transport networks. The result would be the expansion of the transportation capacity, the creation of new transport links, and the modernization of existing ones. For Latvia, as for the European Union member, participation in TEN- T is an important and topical task. Among the 30 priority projects, there is the draft “PR 27 Rail Baltica”, which directly affects Latvia. There will be high-speed sections of the railway on which traffic will be much more intensive than on the Latvian railways at the moment. The growth of rail traffic and the changes in the direction of the movement of cargo tend to inevitably lead to the changes in other modes of transport. The result is the demand for new roads and driveways. At the same time, a more thorough assessment of the resource overpasses, bridges, dams, mode of use has been less intense is requiered. This means that the improvement of diagnostic methods and the control of the elements of the transport infrastructure and rolling stock will be needed. One of techniques that allows diagnosing the accumulation and development of damages in infrastructure projects, units and aggregates of machines, in tanks, pipes or any other objects, is the acoustic emission method (AE). This method belongs to the family of non-destructive testing methods (NDT). The method is based on the principle of the recording and decoding of high-frequency acoustic signals that emit developing defects in materials under the influence of stress. The important circumstance is the fact that the load-AE while monitoring may be used within the normal operating loads, which allows assessing the state of an object without